This invention relates to a circuit arrangement for operating a semiconductor light source, provided with
connection terminals for connecting a power supply, PA1 output terminals for connecting the semiconductor light source.
The invention also relates to a signalling light provided with such a circuit arrangement.
Semiconductor light sources are increasingly used as signalling lights. In such an application, a semiconductor light source has the advantage over a conventional incandescent lamp in that it has a considerably longer useful life and a considerably lower power consumption than the incandescent lamp. Signalling lights often form part of a complicated signalling system, for example, a traffic control system with traffic lights. It is necessary for the circuit arrangement to provide a retrofit possibility in relation to existing signalling systems if the above advantages of semiconductor light sources are to be realized on a wide scale.
The control of a signalling light in existing signalling systems often takes place by means of a status test of the signalling light. A generally used test is the periodic measurement of the value of the current drawn from the power supply. The use of a semiconductor light source is found to lead to a tendency to obtain an incorrect outcome of the status test. This hampers the use of the semiconductor light source as a signalling light in existing signalling systems.